Field of the Invention
The present invention relates to an image capturing apparatus and a method for controlling the same.
Description of the Related Art
Image sensors used in image capturing apparatuses such as digital still cameras and digital video cameras are being provided with more functions, and for example there are known to be image sensors that realizes a phase difference focus detection. Specifically, two photodiodes and one microlens are provided in each pixel of the image sensor. With a configuration in which each photodiode receives light that has passed through different pupil regions in an imaging lens unit, it is possible to perform phase difference focus detection using signals output from the photodiodes. Also, by adding signals output from two photodiodes provided in the same pixel together, image output can be obtained (Japanese Patent Laid-Open No. 2001-124984).
However, with the configuration described in Japanese Patent Laid-Open No. 2001-124984, it is necessary to acquire signals from two photodiodes per pixel. Therefore, in contrast to the conventional configuration in which one pixel has one photodiode, the readout time increases twofold. There is a problem in that at the time of live view shooting or moving image shooting in which readout is performed at a predetermined frame rate, a standby time period per frame is shortened due to the increase in readout time compared to the conventional configuration, resulting in an increase in energy consumption of the image sensor. Also, the amount of heat generated in the image sensor increases due to the increase in energy consumption, as a result of which the temperature of the exterior package of the camera increases. As a result, a period of time in which the temperature of the exterior package reaches an exterior package temperature that is permissible for camera quality decreases, which reduces the amount of time for which imaging can continue.